S100A4 and breast cancer: S100A4 has been shown to cause metastasis in rodent models of breast cancer (Davies et al, 1993, 1996; Ambartsumian et al, 1996), and its presence in breast cancer cells is strongly associated with death of a group of patients with human breast cancer (Platt-Higgins et al, 2000; Rudland et al, 2000).